git.distorted.org.uk Git - u/mdw/catacomb/blob - rabin.h

   1 /* -*-c-*-
   2  *
   3  * $Id: rabin.h,v 1.6 2002/01/13 13:42:53 mdw Exp $
   4  *
   5  * Miller-Rabin primality test
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: rabin.h,v $
  33  * Revision 1.6  2002/01/13 13:42:53  mdw
  34  * More efficient Rabin-Miller test: with random witnesses, skip redundant
  35  * Montgomerization.  (Being bijective, it can't affect the distribution.)
  36  *
  37  * Revision 1.5  2000/07/09 21:32:16  mdw
  38  * rabin_test: Correct error in comment.
  39  *
  40  * Revision 1.4  2000/06/17 11:52:48  mdw
  41  * Typesetting fix.
  42  *
  43  * Revision 1.3  1999/12/22 15:50:29  mdw
  44  * Reworking for new prime-search system.  Add function for working out how
  45  * many iterations to use for a particular number.
  46  *
  47  * Revision 1.2  1999/12/10 23:29:48  mdw
  48  * Change header file guard names.
  49  *
  50  * Revision 1.1  1999/11/19 13:17:57  mdw
  51  * Prime number generator and tester.
  52  *
  53  */
  54
  55 #ifndef CATACOMB_RABIN_H
  56 #define CATACOMB_RABIN_H
  57
  58 #ifdef __cplusplus
  59   extern "C" {
  60 #endif
  61
  62 /*----- Header files ------------------------------------------------------*/
  63
  64 #ifndef CATACOMB_MP_H
  65 #  include "mp.h"
  66 #endif
  67
  68 #ifndef CATACOMB_MPMONT_H
  69 #  include "mpmont.h"
  70 #endif
  71
  72 #ifndef CATACOMB_PFILT_H
  73 #  include "pfilt.h"
  74 #endif
  75
  76 /*----- Data structures ---------------------------------------------------*/
  77
  78 typedef struct rabin {
  79   mpmont mm;                            /* Montgomery arithmetic context */
  80   size_t s;                             /* %$m = 2^s r + 1$% */
  81   mp *r;                                /* %$m = 2^s r + 1$% */
  82   mp *m1;                               /* %$(m - 1)R \bmod m$% */
  83 } rabin;
  84
  85 /*----- Functions provided ------------------------------------------------*/
  86
  87 /* --- @rabin_create@ --- *
  88  *
  89  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  90  *              @mp *m@ = pointer to number to test
  91  *
  92  * Returns:     ---
  93  *
  94  * Use:         Precomputes some useful values for performing the
  95  *              Miller-Rabin probabilistic primality test.
  96  */
  97
  98 extern void rabin_create(rabin */*r*/, mp */*m*/);
  99
 100 /* --- @rabin_destroy@ --- *
 101  *
 102  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
 103  *
 104  * Returns:     ---
 105  *
 106  * Use:         Disposes of a Rabin-Miller context when it's no longer
 107  *              needed.
 108  */
 109
 110 extern void rabin_destroy(rabin */*r*/);
 111
 112 /* --- @rabin_test@, @rabin_rtest@ --- *
 113  *
 114  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
 115  *              @mp *g@ = base to test the number against
 116  *
 117  * Returns:     Either @PGEN_FAIL@ if the test failed, or @PGEN_PASS@
 118  *              if it succeeded.
 119  *
 120  * Use:         Performs a single iteration of the Rabin-Miller primality
 121  *              test.  The @rtest@ variant assumes that %$g$% is either
 122  *              already in Montgomery representation, or you don't care.
 123  */
 124
 125 extern int rabin_rtest(rabin */*r*/, mp */*g*/);
 126 extern int rabin_test(rabin */*r*/, mp */*g*/);
 127
 128 /* --- @rabin_iters@ --- *
 129  *
 130  * Arguments:   @unsigned len@ = number of bits in value
 131  *
 132  * Returns:     Number of iterations recommended.
 133  *
 134  * Use:         Returns the recommended number of iterations to ensure that a
 135  *              number with @len@ bits is really prime.
 136  */
 137
 138 extern int rabin_iters(unsigned /*len*/);
 139
 140 /*----- That's all, folks -------------------------------------------------*/
 141
 142 #ifdef __cplusplus
 143   }
 144 #endif
 145
 146 #endif